Parenteral liquid container and method of making same



Aug. 22, 1967 A. R. SPAETH ET L PARENTERAL LIQUID CONTAINER AND METHOD OF MAKING SAME Filed Dec. 6, 1963 l/V VE/V 70/1 5 4mm li. SPAf/l/ I I 1 I United States Patent 3,337,074 PARENTERAL LIQUID CONTAINER AND METHOD OF MAKING SAME Alfred R. Spaeth, Lake View Terrace, and Thomas P. Stafford, Glendale, Califl, assignors to Don Baxter, Inc.,

Glendale, Calif., a corporation of Nevada Filed Dec. 6, 1963, Ser. No. 328,692 2 Claims. (Cl. 215-79) This invention relates generally to a parenteral liquid container. More particularly, it relates to a container having an improved air tube for admitting air as liquid is removed, and also to a method for making this air tube.

Parenteral liquids, such as dextrose solution or blood, are usually administered from a parenteral liquid container mounted in a mouth-downward position above the level of the patient. As the parenteral liquid flows out of the container, air must enter the container and replace the administered liquid or a vacuum lock will occur. Air may be admitted through a check valve or nonwettable filter in the stopper, but these devices cause the air to bubble up through the parenteral liquid. This causes a risk of administering air into the vein of the patient which can cause an embolism. A safer way of admitting air into the container is through an air tube mounted in an air passage of a stopper in the mouth of this container.

There are, however, certain problems involved in attaching an air tube to an air passage in the stopper, particularly if the air tube is inserted into and extends from the same end of the stopper, rather than being threaded completely through the stopper and extending from the opposite end of the stopper. The air tube must fit firmly enough in the air passage of the stopper to eliminate any chance of accidental dislodgment during shipping or handling. On the other hand, if the air tube is designed to fit too tightly within the stopper, assembling the air tube and the stopper becomes quite difficult. The air tube may become bent or broken when too large a force is required to insert the air tube. Also, slight variations in the size and cross-sectional shape of the air tubes, and slight variations in the diameter of the air passages in the stoppers, can cause different combinations of air tubes and stoppers to fit either too tightly or too loosely. In addition, steam sterilizing temperatures may loosen the air tubes in the stoppers.

We have solved these various problems by a novel configuration on the end of the air tube and a method for making this configuration. Our air tube has, on at least one end, an outwardly extending flange that resembles a blunt arrowhead. In practice, it is preferable to put the flange on both ends of the air tube so these ends need not be oriented when assembling the air tube and stopper. This arrowhead configuration makes the air tube easy to insert in the air passage of a stopper which has a narrow portion in its air passage adjacent its external end and which narrow portion is too small for insertion of the air tube. The purpose of this narrow portion of the air passage is to provide a resilient seat for a plug to cut off the air flow through the air tube when connecting two parenteral liquid containers in series. This is described in a separate application Ser. No. 314,724, filed Oct. 8, 1963, now US. Patent No. 3,230,954. Yet, once the air tube is inserted into the stopper from the internal end, the air tube becomes diflicult to remove, thereby preventing accidental dislodgement. The outside diameter and cross-sectional shape of the air tube and the air passage in the stopper become less critical when the air tube has this arrowhead flange at one end, because the flange extends beyond the outside diameter of the tube to grip the wall of the air passage.

3,337,074 Patented Aug. 22, 1967 An object of this invention is to provide an air tube and stopper combination for a parenteral solution container, the air tube of which is'easy to insert into an air passage in the stopper. This air passage has a narrow portion through which the air tube does not pass, and the air tube is firmly held in the stopper once inserted.

Another object of this invention is to provide an air tube and stopper combination for a parenteral liquid container, wherein the air tube has a novel flange which allows the air tube to be easily inserted part way through an air passage of the stopper from the internal end of this stopper.

Still another object of this invention is to provide a method for producing a novel flange at the end of a thermoplastic air tube.

Other objects of our invention will become apparent upon further description, of which the following are illustrations FIGURE 1 is a front elevational view of a parenteral liquid container in a mouth downward position, showing an air tube in dotted line mounted in the stopper of this container;

FIGURE 2 is an enlarged view partially in section of the stopper and air tube assembly;

FIGURE 3 is an enlarged sectional view of the air tube and stopper of FIGURE 2;

FIGURE 4 is an enlarged sectional View of the air tube vafter it has been cut to length, but before it has been flanged;

FIGURE 5 is an enlarged sectional view of the lower end of the air tube of FIGURE 2; and

FIGURE 6 is a sectional view of a glass tubing, the end of which has been fire polished.

The parenteral liquid container shown in FIGURE 1 is supported in a mouth-downward position by a bail 2. The container 1 is shown partially filled with a liquid 3, thereby leaving an tillage 4 at one end of the container. In administering liquid from container 1, an administration tube 7 is connected by means of a needle (not shown) to a patient, and the liquid 3 flows out of. the container through drip housing 8, through administration tube 7, and into the patient. As liquid 3 is administered, air flows in through air tube 5 to replace the volume of liquid administered. Air tube 5 is held in the position shown in FIGURE 1 by a resilient stopper 9, which is held firmly in the mouth of container 1 by metal band 6.

An enlarged view of the stopper 9 and air tube 5 is shown in FIGURE 2. Here, the sectional view of the stopper shows a liquid outlet passage 10 and an air inlet passage 11. The spike of drip housing 8 is inserted into 'liquid outlet passage 10, and the air tube is inserted into the air inlet passage 11. In order to prevent the air tube 21 is provided in the air passage. This shoulder is located at the point where the air passage narrows to form a narrow portion 22. This narrow portion 22 is shown adjacent the external end 24 of the stopper. At one end of air tube 5 is an outwardly extending flange 12 which can abut against shoulder 21 and firmly grip the wall 20 of air passage 11, thereby preventing dislodgment of the air tube 5.

The reason for flange 12 firmly gripping wall 20 to prevent dislodgment, and at the same time being easily insertable into air inlet passage 11 from the internal end 23 of the stopper, is illustrated in FIGURES 3 and 5 which show the configuration of flange 12. Flange 12 includes a retaining ledge surface 13 which is spaced inwardly from the end of air tube 5. This retaining ledge surface extends outwardly from the outer surface of the air tube and is joined at its periphery by a rounded nose surface 14. Nose surface 14 converges radially inwardly from the periphery of ledge surface 13' to a tip 15. Preferably, this tip is circular and has a smaller diameter than the outside diameter of the air tube. Thus, flange 12 takes on a configuration that is roughly that of a blunt arrowhead having an axial bore. At the end of this bore is a mouth 19 which is approximately the same size as the bore of air tube 5.

The method of making the above-described flange involves fiame treating the end of an air tube made of extruded thermoplastic material, such as polyethylene or polypropylene. This method is much less expensive than injection molding, machining, swagging, or other methods of forming a flange. When the end of our tube is heated to its fusion point, the outer surface begins to curl and form the illustrated arrowhead configuration. Upon cooling, the flange hardens and can then be easily inserted into air inlet passage 11 and firmly seat therein.

The shape of flange 12 and the fact that producing it by flame treating does not materially restrict mouth 19 is a completely unexpected result. Comparing flange 12 with the fire polished end 17 of a glass tube 16 shown in FIGURE 6 points out this unexpected result. Flame treating a glass tube merely rounds off the edges of a square cut end as expected, and sometimes forms a constriction at month 18. The fire polished end of glass tube 16 would do nothing to hold the tube more firmly than an unpolished tube in air passage 11.

The reason for the unexpected behavior of a thermoplastic air tube when flame treated is not completely understood. The air tubes are of extruded thermoplastic, such as polypropylene and polyethylene, and the extrusion process itself may contribute to this behavior. Perhaps one reason is the greater molecular stretching at the outer surface caused by the extrusion. Heating the end of the air tube to its fusion point may then tend to relax the molecules at the outer surface more than the molecules elsewhere in the tube.

Although we have shown one embodiment of our invention for illustrative purposes, it is understood that those skilled in the art can make certain modifications without departing from the spirit and scope of our in vention.

We claim:

1. In a parenteral liquid container adapted to dispense liquid while in a mouth-downward position, the improvement comprising:

(a) a stopper closing the mouth of said container, said stopper having at least a liquid outlet passage and an air inlet passage, said air inlet passage connecting an internal end of said stopper in contact with the interior of said container with an external end of said stopper so as to channel air through said stopper, said air passage having a narrow portion.

spaced from said internal end;

(b) a plastic air tube fitting within said air inlet passage, one end of said air tube extending downwardly from the internal end of said stopper to the narrow portion of said air passage and the opposite end of said air tube extending upwardly into said container to connect the ullage of said container while in its mouth-downward position with said air passage; and

(c) an outwardly extending flange on at least the end of said air tube fitting within said air passage, said flange engaging the walls of said air inlet passage, said flange having a retaining ledge surface spaced from the tip of said air tube and extending outwardly from said air tube to a periphery of said retaining ledge surface, and a smooth nose surface extending from the periphery of said ledge surface and converging radially inwardly to provide a tip of said air tube, which tip is smaller in diameter than the outside diameter of the air tube and which is easily inserted into the air passage of said stopper.

2. In a parenteral liquid container adapted to dispense liquid while in a mouth-downward position, the improvement comprising:

(a) a stopper closing the mouth of said container, said stopper having at least a liquid outlet passage and an air inlet passage, said air inlet passage connecting an internal end of said stopper in contact with the interior of said container with an external end of said stopper so as to channel air through said stopper;

(b) a plastic air tube fitting within said air inlet passage, one end of said air tube extending into the air inlet passage from the internal end of the stopper and the opposite end of said air tube extending upwardly into said container to connect the ullage of said container while in its mouth-downward position with said air passage; and

(c) an outwardly extending flange on at least the end of said air tube fitting within said air passage, said flange engaging the walls of said air inlet passage, said flange having a retaining ledge surface spaced from the tip of said air tube and extending outwardly from said air tube to a periphery of said retaining ledge surface, and a smooth nose surface extending from the periphery of said ledge surface and converging radially inwardly to provide a tip of said air tube, which tip is smaller in diameter than the outside diameter of the air tube and which is easily inserted into the air passage of said stopper.

References Cited UNITED STATES PATENTS 2,004,027 6/ 1935 Baxter. 2,517,661 8/1950 Hart 264-80 2,848,749 8/1958 Tobias 264---80 2,969,158 l/1961 Baumann 2l5-79 3,067,898 12/1962 Reinmann 21579 3,219,036 11/1965 Stafford 12r8214 THERON E. CONDON, Primary Examiner.

FRANKLIN T. GARRETT, Examiner.

J. B. MARBERT, Assistant Examiner. 

1. IN A PARENTERAL LIQUID CONTAINER ADAPTED TO DISPENSE LIQUID WHILE IN A MOUTH-DOWNWARD POSITION, THE IMPROVEMENT COMPRISING: (A) A STOPPER CLOSING THE MOUTH OF SAID CONTAINER, SAID STOPPER HAVING AT LEAST A LIQUID OUTLET PASSAGE AND AN AIR INLET PASSAGE, SAID AIR INLET PASSAGE CONNECTING AN INTERNAL END OF SAID STOPPER IN CONTACT WITH THE INTERIOR OF SAID CONTAINER WITH AN EXTERNAL END OF SAID STOPPER SO AS TO CHANNEL AIR THROUGH SAID STOPPER, SAID AIR PASSAGE HAVING A NARROW PORTION SPACED FROM SAID INTERNAL END; (B) A PLASTIC AIR TUBE FITTING WITHIN SAID AIR INLET PASSAGE, ONE END OF SAID AIR TUBE EXTENDING DOWNWARDLY FROM THE INTERNAL END OF SAID STOPPER TO THE NARROW PORTION OF SAID AIR PASSAGE AND THE OPPOSITE END OF SAID AIR TUBE EXTENDING UPWARDLY INTO SAID CONTAINER TO CONNECT THE ULLAGE OF SAID CONTAINER WHILE IN ITS MOUTH-DOWNWARD POSITION WITH SAID AIR PASSAGE; AND (C) AN OUTWARDLY EXTENDING FLANGE ON AT LEAST THE END OF SAID AIR TUBE FITTING WITHIN SAID AIR PASSAGE, SAID FLANGE ENGAGING THE WALLS OF SAID AIR INLET PASSAGE, SAID FLANGE HAVING A RETAINING LEDGE SURFACE SPACED FROM THE TIP OF SAID AIR TUBE AND EXTENDING OUTWARDLY FROM SAID AIR TUBE TO A PERIPHERY OF SAID RETAINING LEDGE SURFACE, AND A SMOOTH NOSE SURFACE EXTENDING FROM THE PERIPHERY OF SAID LEDGE SURFACE AND CONVERGING RADIALLY INWARDLY TO PROVIDE A TIP OF SAID AIR TUBE, WHICH TIP IS SMALLER IN DIAMETER THAN THE OUTSIDE DIAMETER OF THE AIR TUBE AND WHICH IS EASILY INSERTED INTO THE AIR PASSAGE OF SAID STOPPER. 